Conventionally, as for this type of a pipe connecting connector, there is known a pipe connecting connector comprising a connector main body wherein the pipe is inserted and removed; and a lock member slidably held in the connector main body, and fixing the inserted pipe. In the lock member, there is formed a holding arm held inside a hole opening on a peripheral face of the connector main body, and including a hook which can be displaced in a radial direction of the connector. The hook includes an inclined surface on an outer side in a radial direction of an end thereof. When the lock member moves in a direction of fixing the pipe, the hook engages with a bulge portion of the pipe and fixes the pipe. Also, the inclined surface thereof is pressed by a peripheral edge of the hole of the connector main body, so that a movement in the radial direction thereof is controlled (see Patent Document 1).
Also, in the conventional connector, when a release arm, which has been connected to a back end side of the holding arm, is pressed, the lock member moves in a direction of releasing a fixation of the pipe. Thereby, a pressing force relative to the inclined surface of the hook is released, and the hook can move to the outer side in the radial direction (a direction of being capable of releasing a connection of the pipe).